an African American and a Japanese American look completely different, but when they are dead, their bones are completely the same.
Actually, that's completely false. Medical examiners regularly discern things like race from completely skeletal remains.
what would make you think that one was african american and one was japanese american just by looking at the bones?
Typically, they consider the length of the long bones, the width of the pelvis, and the structure of the skull to determine race. I'm not a doctor so I can't be more specific.
You really have no idea what a set of bones can tell someone, do you?